#include <QApplication>
#include <QTextCodec>
#include <QWidget>
#include <QString>
#include <QFileDialog>
#include <opencv.hpp>

using namespace cv;

int main( int argc, char** argv )
{
	QApplication a(argc, argv);
	//Qt的中文支持
	QTextCodec*codec=QTextCodec::codecForName("GBK");  
	QTextCodec::setCodecForLocale(codec);  
	QTextCodec::setCodecForTr(codec);  
	QTextCodec::setCodecForCStrings(codec); 

	QString imagesDir = "I:\\Images";

	QWidget* widget = new QWidget;
	QString fileName = QFileDialog::getOpenFileName(widget,"Open image",
		imagesDir,"Images (*.jpg *.bmp *.png)");
	if (fileName.isEmpty())
		return -1;

	cv::Mat _srcImg = cv::imread(fileName.toStdString(),CV_LOAD_IMAGE_COLOR);
	CV_Assert(!_srcImg.empty());

	/// Separate the image in 3 places ( B, G and R )
	vector<Mat> bgr_planes;
	split( hsvImg, bgr_planes );

	/// Establish the number of bins
	int histSize = 256;

	/// Set the ranges ( for B,G,R) )
	float range[] = { 0, 256 } ;
	const float* histRange = { range };

	bool uniform = true; bool accumulate = false;

	Mat b_hist, g_hist, r_hist;

	/// Compute the histograms:
	calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate );
	calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
	calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );

	// Draw the histograms for B, G and R
	int hist_w = 512; int hist_h = 400;
	int bin_w = cvRound( (double) hist_w/histSize );

	Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );

	/// Normalize the result to [ 0, histImage.rows ]
	normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
	normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
	normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );

	/// Draw for each channel
	for( int i = 1; i < histSize; i++ )
	{
		line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ) ,
			Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ),
			Scalar( 255, 0, 0), 2, 8, 0  );
		line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ) ,
			Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
			Scalar( 0, 255, 0), 2, 8, 0  );
		line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ) ,
			Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
			Scalar( 0, 0, 255), 2, 8, 0  );
	}

	/// Display
	namedWindow("calcHist Demo", CV_WINDOW_AUTOSIZE );
	imshow("calcHist Demo", histImage );

	waitKey(0);

	return 0;
}